Prognostic Evaluation of Nodal Staging Based on the New IASLC Lymph Node Map for Lung Cancer

Abstract

Background: The purpose of this study was to evaluate the new lymph node map proposed by the International Association for the Study of Lung Cancer (IASLC) from the point of prognosis, and to identify the significant prognostic factors in each pathological N stage. Methods: We reviewed 647 consecutive patients with surgically resected non-small cell lung cancers. Survival was analyzed according to N stage and three prognostic subgroups: N1a (single N1 zone), N1b (multiple N1 zones) or N2a (single N2 zone), and N2b (multiple N2 zones). The following prognostic factors were evaluated for each N stage: location of involved zones, number of involved lymph nodes, stations and zones, and the presence of skip metastases. Results: (1) The survival curves showed a stepwise deterioration as the N stage increased. (2) No significant difference was observed in survival between the different locations of involved zones in each N stage. (3) In N2 patients, the presence of skip metastases was a significant prognostic factor in multivariate analysis. Conclusions: The proposed IASLC map is valid for prognostic stratification. The prognostic impact of the presence of skip metastases on N2 disease should therefore be taken into consideration when carrying out the forthcoming revision of the TNM staging system.

Key words

lung cancer - lymph node - staging

References

• 1 Mountain C F. Revisions in the international system for staging lung cancer.  Chest. 1997;  111 1710-1717
• 2 Sobin L, Wittekind C. International Union Against Cancer (UICC): TNM classification of malignant tumors. 6th ed. New York; John Wiley & Sons 2002
• 3 Goldstraw P. Staging manual in thoracic oncology. Orange Park, FL, USA; Editorial Rx Press 2009
• 4 Rusch V W, Crowley J, Giroux D J et al. The IASLC lung cancer staging project: proposals for the revision of the N descriptors in the forthcoming seventh edition of the TNM classification for lung cancer.  J Thorac Oncol. 2007;  2 603-612
• 5 Naruke T. [The spread of lung cancer and its relevance to lung surgery].  Nippon Kyobu Geka Gakkai Zasshi. 1967;  68 1607-1621
• 6 Naruke T, Suemasu K, Ishikawa S. Lymph node mapping and curability at various levels of metastasis in resected lung cancer.  J Thorac Cardiovasc Surg. 1978;  76 832-839
• 7 Mountain C F, Dresler C M. Regional lymph node classification for lung cancer staging.  Chest. 1997;  111 1718-1723
• 8 Rusch V W, Asamura H, Watanabe H et al. The IASLC lung cancer staging project: a proposal for a new international lymph node map in the forthcoming seventh edition of the TNM classification for lung cancer.  J Thorac Oncol. 2009;  4 568-577
• 9 Sakao Y, Miyamoto H, Oh S, Takahashi N, Sakuraba M. Clinicopathological factors associated with unexpected N3 in patients with mediastinal lymph node involvement.  J Thorac Oncol. 2007;  2 1107-1111
• 10 Sakao Y, Miyamoto H, Yamazaki A et al. The spread of metastatic lymph nodes to the mediastinum from left upper lobe cancer: results of superior mediastinal nodal dissection through a median sternotomy.  Eur J Cardiothorac Surg. 2006;  30 543-547
• 11 World Health Organization .Histological typing of lung and pleural tumours. 3rd ed. Geneva; World Health Organization 1999
• 12 Goldstraw P, Crowley J, Chansky K et al. The IASLC lung cancer staging project: proposals for the revision of the TNM stage groupings in the forthcoming (seventh) edition of the TNM Classification of malignant tumours.  J Thorac Oncol. 2007;  2 706-714
• 13 Demir A, Turna A, Kocaturk C et al. Prognostic significance of surgical-pathologic N1 lymph node involvement in non-small cell lung cancer.  Ann Thorac Surg. 2009;  87 1014-1022
• 14 Andre F, Grunenwald D, Pignon J P et al. Survival of patients with resected N2 non-small-cell lung cancer: evidence for a subclassification and implications.  J Clin Oncol. 2000;  18 2981-2989
• 15 Okada M, Sakamoto T, Yuki T et al. Border between N1 and N2 stations in lung carcinoma: lessons from lymph node metastatic patterns of lower lobe tumors.  J Thorac Cardiovasc Surg. 2005;  129 825-830
• 16 Fukui T, Mori S, Yokoi K, Mitsudomi T. Significance of the number of positive lymph nodes in resected non-small cell lung cancer.  J Thorac Oncol. 2006;  1 120-125
• 17 Keller S M, Vangel M G, Wagner H et al. Prolonged survival in patients with resected non-small cell lung cancer and single-level N2 disease.  J Thorac Cardiovasc Surg. 2004;  128 130-137
• 18 Misthos P, Sepsas E, Kokotsakis J, Skottis I, Lioulias A. The significance of one-station N2 disease in the prognosis of patients with nonsmall-cell lung cancer.  Ann Thorac Surg. 2008;  86 1626-1630
• 19 Prenzel K L, Baldus S E, Monig S P et al. Skip metastasis in nonsmall cell lung carcinoma: predictive markers and isolated tumor cells in N1 lymph nodes.  Cancer. 2004;  100 1909-1917
• 20 Riquet M, Assouad J, Bagan P et al. Skip mediastinal lymph node metastasis and lung cancer: a particular N2 subgroup with a better prognosis.  Ann Thorac Surg. 2005;  79 225-233
• 21 Tsubota N, Yoshimura M. Skip metastasis and hidden N2 disease in lung cancer: how successful is mediastinal dissection?.  Surg Today. 1996;  26 169-172
• 22 Riquet M, Hidden G, Debesse B. Direct lymphatic drainage of lung segments to the mediastinal nodes. An anatomic study on 260 adults.  J Thorac Cardiovasc Surg. 1989;  97 623-632
• 23 Lardinois D, De Leyn P, Van Schil P et al. ESTS guidelines for intraoperative lymph node staging in non-small cell lung cancer.  Eur J Cardiothorac Surg. 2006;  30 787-792